Unmanned aerial vehicle is used the earliest for military purpose, such as long-range investigation and spy monitoring. Civil unmanned aerial vehicle has been being developed rapidly for these years and applied mostly to fields such as earth monitoring, disaster prevention and relief, and commercially aerial photography, and so on. Unmanned aerial vehicle is of many advantages, such as high flexibility, lower operation cost compared with traditional aircraft, fewer damages on people because of no passenger on it, and higher safety.
Unmanned aerial vehicle is capable of vertical taking off and landing without takeoff site and runway, so that it may execute tasks of various application fields. Along with different application fields, there are more and more function requirements for unmanned aerial vehicle to be increasingly developed. Present general unmanned aerial vehicle is driven to fly by a throw-up way and driven to automatically fly by detecting whether unmanned aerial vehicle falls down or not. However, it is not intuitive for a user to make unmanned aerial vehicle fly by the throw-up way. Furthermore, if it spends too much time on detecting whether unmanned aerial vehicle falls down or not, unmanned aerial vehicle does not automatically fly possibly to further cause failure in flying. The situations aforementioned are necessarily improved.